A radiological system comprises a source of ionizing radiation, such as for example an x-ray tube, allowing x-ray radiation to be generated, and a base station comprising an information-processing system allowing the x-ray tube and the detector to be synchronized and also allowing image processing operations to be carried out so as to present the operator with an image that is corrected for any inherent defects in the detector and improved, for example via edge-restoring processing. An object the x-ray image of which it is desired to obtain is placed between the source and the detector. Such a system may be used in many applications such as for example medical radiology and nondestructive testing. The invention may also be implemented with other types of radiation to be detected, in particular gamma radiation.
In the past, radiological systems were bulky and difficult to move. It was necessary to position the object with respect to the system in order to obtain the desired image. With the appearance of solid-state detectors, the detector has become less bulky and it has become possible to move the detector with respect to an object that remains stationary. For medical radiology, digital detectors have been produced in the form of movable cassettes that it is possible to place in immediate proximity to a patient an image of whom it is desired to take, when the state of health of the patient prevents them from moving to a room reserved for radiology.
Movable cassette essentially comprises a digital detector of ionizing radiation taking the form of a flat panel and a circuit board that in particular controls the digital detector. The detector and the board are placed in a housing that protects them mechanically.
In mobile radiography, for example when the radiography is carried out at the bedside of a patient who is unable to move, it is essential for the radiograph obtained to be associated with this patient. Generally therefore, each obtained radiograph must be associated with the right patient.
The radiography may be carried out by means of what are called analog cassettes i.e. cassettes of film/screen type or of photostimulable-phosphor-plate cassettes (also known as PSP cassettes from the abbreviation of photostimulable phosphor plate or as CR cassettes from the abbreviation of computed radiography). Radiographs are achieved with PSP cassettes by virtue of a film integrated into the cassette, which is able to store an image. The film is read subsequently by a separate reader in a workstation. Thus, a cassette allows only a single radiograph to be taken at a time. Operators who want to take a plurality of radiographs of various patients must therefore provide a plurality of cassettes, thereby creating a risk of mix-up of the cassettes and of confusion as to the identification of the patients. It is possible to stick a label with the name or the code of the patient on the back of each cassette, in order to decrease the risk of incorrect attribution of the image to the patient during the development of the radiograph. The labels may be taken from the bedside of the patient or be printed beforehand. This solution is nevertheless not completely satisfactory in a hospital environment. Specifically, radiographs taken at the bedside of patients are generally taken during a ward round. It is necessary to provide a plurality of cassettes, and the risk of confusion as to the identification of the patient remains.
Another solution consists in generating codes (for example barcodes). A cassette receives a barcode. The operator notes on the cassette the name of the patient, and optionally the radiographed part. Using a barcode reader, the code is read out and the image that will be produced is then attributed to the patient chosen by the operator. This solution involves the barcode being read out after the ward round, at the workstation. It therefore requires the operator to open, at the workstation, the record of the right patient before initiating the cassette readout. The risk of confusion between patients and images is still present and it is still necessary to provide a plurality of cassettes if a plurality of radiographs are to be taken, this being burdensome.
As mentioned above, cassettes that are what are called digital cassettes and that are sensitive to x-ray radiation do exist. There is no need for a digital cassette to be connected to the x-ray generator, the cassette detects x-rays by itself and records images as they are taken. In other words, a single digital cassette may contain a plurality of images. This solution has the advantage that the operator no longer needs to take a plurality of cassettes with him when he is required to take a plurality of radiographs. In contrast, once again, the risk of confusion as to the identification of the patient to which each stored image corresponds is real since the digital cassette contains a plurality of images and it is necessary to be able to determine to which patient each of the produced images stored in the cassette corresponds. One possible way of decreasing the risk of confusion as to the identification of the patient is to attribute a barcode to the patient, which barcode is read out, before the radiography, with an additional barcode reader by the operator. This readout allows the record of the patient to be opened on the computer of the mobile radiology apparatus. However, such a solution therefore requires a mobile radiology system comprising a cassette reader and a computer to acquire the image. This solution is not stand-alone since it is necessary to provide a trolley with a computer and cassette reader. In addition, this solution is not compatible with adaptation to pre-existing structures for cassettes designed to hold silver-based films of dimensions defined by standard ISO4090.
One solution consists in integrating a small screen into the digital cassette. This small screen allows a number that is incremented each time an image is taken to be displayed. This number therefore corresponds to the number of images stored in memory in the detector. Radiograph number 1 belongs to the first patient, radiograph number 2 belongs to the second patient, etc. Or indeed, if the operator is required to take a plurality of radiographs of the same patient, radiograph number 1 may belong to a first patient, radiograph number 2 may belong to patient number 2, and radiograph number 3 may belong to the same patient number 2. Moreover, in addition to identifying the patient, it is necessary to identify what part of the body was radiographed. The risk of mix-up between stored images and patients is high during the download of the images to the workstation. Specifically, it is up to the operator to manually note, for example on the chart of the patient or in his own clinical notes, the number displayed on the small screen of the cassette when he takes a radiograph of a patient, and optionally the radiographed part of the body. If the operator wants to avoid this source of error due to manual notation of the displayed number on the chart of the patient, it is possible to attribute beforehand codes to the patients. But this solution then obliges the operator to respect, when taking the radiographs, the numerical order thus established. In other words, if the displayed number is considered to be an identification code of the patient (the number 1 being defined beforehand as being attributed to such a patient, the number 2 being attributed to another such patient, etc.), the order in which the radiographs must be taken is set beforehand and if not respected may lead to stored images and patients being incorrectly associated during the download of the images to the workstation.